@Simona563 I've had guests ask about my decor and furnishings, too, and have actually thought of something along the lines of what you propose. There was a show on Netflix called "Stay Here," which had HGTV interior design star Genevieve Gorder go around renovating places so their owners could put them on Airbnb. At one place (I think it was the carriage house in Hudson, NY), she had the owner partner with a local antique dealer to bring some unique pieces into the space and then potentially sell them. I don't think I will actually do it, but if I get another space to turn into an Airbnb I would definitely consult with some of my antique dealer friends and brainstorm with getting them involved in some way.
I think it's possible to do, and agree with you it shouldn't appear salesy at all, but should appeal to the guest's wish to bring some style home from the trip. In other words, it should feel like added value to the guest, not like pressure to spend more money.